Increased Heparanase Level and Procoagulant Activity in Orthopedic Surgery Patients Receiving Prophylactic Dose of Enoxaparin,

Abstract

Abstract 3333 Background:Orthopedic hip and knee surgeries are followed by a hypercoagulable state. Heparanase is implicated in inflammation, coagulation activation and angiogenesis. Recently, heparanase was shown to directly interact with tissue factor (TF) and to enhance generation of factor Xa (Nadir et al, Haematologica, 2010). In addition, an assay evaluating heparanase procoagulant activity has been lately developed (Nadir et al, Thromb Res, 2011). In the present study, heparanase level and procoagulant activity in patients undergoing orthopedic surgery were assessed. Methods: The study group included 50 orthopedic patients. Thirty one patients underwent hip operation and 19 had knee surgery. Fifteen individuals suffered from traumatic hip fractures and 35 had osteoarthrosis of hip or knee joints. All patients received a prophylactic dose of enoxaparin starting 6–8 hours post operation and lasting for 5 weeks. Plasma samples were drawn preoperatively and at 1 hour, 1 week and 1 month post surgery. Samples were tested for heparanase levels by ELISA and TF/heparanase complex activity, TF activity, heparanase procoagulant activity, factor Xa and thrombin levels were estimated using chromogenic substrates. Results: Heparanase levels were significantly higher 1 hour and 1 week postoperatively compared to preoperative levels (p<0.05, p<0.005, respectively). The most dramatic changes were observed in heparanase procoagulant activity, reaching a 2-fold increase 1 week postoperatively and a 1.7-fold increase 1 month after surgery (p<0.0001 and p<0.0001, respectively). Levels of factor Xa and thrombin did not significantly change. Conclusions: Heparanase is found to be involved in coagulation activation of orthopedic surgery patients, with heparanase procoagulant activity being highest 1 week postoperatively and still remaining high 1 month after operation. Consideration of extending prophylactic anticoagulant therapy or evaluation of heparanase procoagulant activity may potentially prevent late thrombotic events in this patient population. Disclosures:No relevant conflicts of interest to declare.